• Title/Summary/Keyword: 초기사이징

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Development of Conceptual Design Methodology and Initial Sizing for Tip-Jet Gyroplane (Tip-jet gyroplane 개념설계 기법 개발 및 사이징)

  • Lee, Donguk;Lim, Daejin;Yee, Kwanjung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.6
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    • pp.452-463
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    • 2018
  • Tip-jet gyroplane is a type of compound helicopter that employs the tip-jet system to rotate the rotor by a reaction force from the gas jetted at the rotor tips in hovering. In forward flight, tip-jet gyroplane converts into a form of a gyroplane. Therefore, it is necessary to develop a new conceptual design method to consider three flight modes: tip-jet mode, gyroplane mode, and transient mode. This study developed the numerical code of conceptual design methodology that can consider three flight modes. The developed code was validated against the available experiment data. Based on the developed code, initial sizing of tip-jet gyroplane was performed for two mission profiles including high speed forward flight of 150knots with a mission range of 300km or 400km. Subsequently, the configuration and performance of the 3,000lb tip-jet gyroplane were analyzed.

Airframe Weight Estimation Method for Initial Sizing of Multicopter (멀티콥터 초기 사이징을 위한 기체 구조 중량 예측 기법)

  • Jang, Byeong-Wook;Hwang, In-Seong;Kim, Minwoo;Lee, Bosung;Jung, Yongwun;Kang, Wanggu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.9
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    • pp.723-734
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    • 2018
  • A structural weight estimation methodology for the multicopter design process is presented. In general, a multicopter is composed of an airframe, motors, propellers, battery and so on. Among these, the weight of motors, propellers and battery can be obtained from the weight trends with respect to design parameters. However, the structural weight is hard to be estimated due to the various configurations and design concepts of multicopters. Moreover, the airframe weights of most commercial multicopter products are not provided. Thus, an accurate airframe weight model is required for the reliable mutlcopter design process. Firstly, the standard configuration of multicopters is defined. Then, we proposed the structural weight estimation method using the number and diameter of propellers determined from the initial step of sizing process. Finally, we validated our suggested method using the commerical products.

Initial Sizing of a Glider Type High Altitude Long Endurance Unmanned Aerial Vehicle Using Alternative Energy (대체에너지를 사용한 글라이더형 고고도 장기체공 무인항공기의 초기사이징)

  • Han, Hye-Sun;Kim, Chan-Eol;Hwang, Ho-Yon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.1
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    • pp.47-58
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    • 2014
  • In this research, the initial sizing of a HALE(High Altitude Long Endurance) UAV which uses solar power and hydrogen fuel cell as an alternative energy was performed. Instead of a wing box type, a glider type was chosen since it is relatively easy to get a data thanks to many researches abroad. Maximum takeoff weight is around 150Kg and the propulsion system is composed of motor, propeller, solar cell, and hydrogen fuel cell which can be recharged through electrolysis. Maximum takeoff weight was estimated as aspect ratio, wing span, wing area change while considering energy balance of required energy which is necessary for flight during the entire day and available energy which can be taken from the solar cell.

Initial Sizing of General Aviation Aircraft Propelled by Electric Propulsion system (전기로 추진되는 일반 프로펠러 항공기의 초기 사이징)

  • Han, Hye-Sun;Shin, Kyo-Sic;Park, Hong-Ju;Hwang, Ho-Yon;Nam, Taewoo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.5
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    • pp.391-403
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    • 2013
  • Propeller aircraft propelled by an electric propulsion system is gaining a renewed interest because of ever-increasing environmental concern on harmful emissions emitted from conventional jet engines and national energy security. Traditional aircraft sizing methods are not readily applicable to electric propulsion aircraft that utilize a variety of alternative energy sources and power generation systems. This study showcases an electric propulsion aircraft sizing exercise based on a generalized, power based sizing method. A general aviation aircraft is propelled by an electric propulsion system that comprises of a propeller, a high temperature super conducting motor, a Proton Exchange Membrance(PEM) fuel cell system fuelled with hydrogen, and power conditioning equipment. In order to assess the impact of technology progression, aircraft sizing was conducted for two different sets of technology assumptions for electric components, and the results were compared with conventional baseline aircraft.

Initial Sizing of a Tilt Ducted Fan Type eVTOL for Urban Air Mobility (도심항공 모빌리티(UAM)를 위한 틸트 덕티드 팬 형 eVTOL의 초기 사이징)

  • Lee, Sang Gon;Ko, Bo Sung;Ahn, Seong Ho;Hwang, Ho Yon
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.29 no.3
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    • pp.52-65
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    • 2021
  • A large amount of time and cost is consumed due to congestions caused by an increasing number of cars which results in a lot of emissions. To overcome these problems, a new electric vertical takeoff and landing (eVTOL) aircraft is being considered. Since vertical take off and landing without a separate runway is realized and electricity is used as a power source, it could solve the saturated ground traffic congestions without emissions. In this paper, the initial sizing was performed based on the Nexus 6HX of Belltextron which is a tilt-ducted fan type. In this study, the electric propulsion system that only uses battery was implemented instead of current Nexus 6HX hybrid electric propulsion. Aerodynamic analyses were performed using OpenVSP and XFLR5. Power-to-weight ratio, wing loading, estimated weight were calculated with these analyses.

Energy Balance and Constraints for the Initial Sizing of a Solar Powered Aircraft (태양광 추진 항공기의 초기 사이징을 위한 에너지 균형 및 구속조건 연구)

  • Hwang, Ho-Yon;Nam, Tae-Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.6
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    • pp.523-535
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    • 2012
  • Solar powered aircraft are becoming more and more interesting for future long endurance missions at hight altitudes, because they could provide surveillance, earth monitoring, telecommunications, etc. without any atmospheric pollution and hopefully in the near future with competitive costs compared with satellites. However, traditional aircraft sizing methods currently employed in the conceptual design phase are not immediately applicable to solar powered aircraft. Hence, energy balance and constraint analyses were performed to determine how various power system components effect the sizing of a solar powered long endurance aircraft. The primary power system components considered in this study were photovoltaic (PV) modules for power generation and regenerative fuel cells for energy storage. To verify current research results, these new sizing methods were applied to HALE aircraft and results were presented.

Initial Sizing of a Roadable PAV Considering Airfoil and Engine Types (익형과 엔진 종류를 고려한 도로주행형 PAV 초기 사이징)

  • Cha, Jae-Young;Hwang, Ho-Yon
    • Journal of Advanced Navigation Technology
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    • v.23 no.1
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    • pp.44-54
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    • 2019
  • In many countries, there are needs of new transportations to replace ground congestions due to growing number of cars. In addition, the increase in the number of cars held by economic growth will further increase traffic congestion in the future. To overcome this problem, many researches have been performed for personal air vehicle (PAV). In this study, the wing loading and the power-to-weight ratio that are major design parameters for the sizing of roadable PAVs were calculated for different kinds of airfoil and engine types. I.e., in the sizing process, the study was conducted to determine the design point using the graphs of wing loading, power-to-weight ratio, brake horse power, and fuel efficiency for the given mission profiles considering domestic environments and the FAR PART 23 which is the GA class aircraft certification standard. As a result of sizing, using diesel engine require high maximum take-off weight, wing area, and power compared to gasoline engine due to more engine weight.

Battery Sensitivity Analysis on Initial Sizing of eVTOL Aircraft (전기 추진 수직이착륙기의 초기 사이징에 대한 배터리 민감도 분석)

  • Park, Minjun;Choi, Jou-Young Jason;Park, Se Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.12
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    • pp.819-828
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    • 2022
  • Sensitivity of aircraft sizing depending on battery performance was studied for a generic quad tilt rotor type electric vertical takeoff and landing vehicle. The mission requirements proposed by Uber Elevate and NASA were used for initial sizing, and the calculated gross weight is ranged between 5,000lb and 11,000lb for battery specific energy range of 200-400Wh/kg in pack level and continuous discharge rate range of 4-5C. For the assumed gross weight of 7,000lb, the required battery performance was calculated with two different criteria: available power and energy, and the effects of battery specific energy and discharge rate are analyzed. The maximum discharge rate is also recommended considering failure cases such as one battery pack inoperative and one prop rotor inoperative.

Analysis and Trend Curve Derivation of Major Design Parameters of Unmanned and Manned Rotorcrafts (유.무인 회전익기 주요 설계변수의 추세선 식 유도 및 비교 분석 연구)

  • Hwang, Chang-Jeon;Kim, Seung-Beom
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.2
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    • pp.26-35
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    • 2006
  • Design parameters of manned and unmanned rotorcrafts have been investigated to construct a design database and to derive trend curves. Design parameters of 78 manned rotorcrafts and 33 unmanned rotorcrafts have been collected and analyzed using linear regression method. Six kinds of trend curves equations are derived. Most of trend curves derived are relatively meaningful according to the calculated correlation and determination coefficients. The comparisons between manned and unmanned rotorcraft characteristics are performed. It has been drawn according to the comparisons that unmanned rotorcraft has smaller main rotor diameter and maximum take-off weight, bigger tail rotor size and similar level of empty weight fraction than manned rotorcraft.

Evaluation of Process Performance and Mechanical Properties according to Process Variables of Pneumatic Carbon Fiber Tow Spreading (공기에 의한 탄소섬유 스프레딩 공정 변수에 따른 프로세스 성능 및 기계적 물성 평가)

  • Roh, Jeong-U;Baek, Un-Gyeong;Roh, Jae-Seung;Nam, Gibeop
    • Composites Research
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    • v.33 no.6
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    • pp.390-394
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    • 2020
  • The carbon fiber has been damaged via tow spreading process for carbon fiber spread tow. The fiber damage is caused by friction between equipment and fibers or between fibers and fibers in the process of spreading. As a result, mechanical properties are decreased due to differences in process via material and equipment condition. Therefore, minimizing fiber damage have to be considered in the process. In this study, the change in carbon fiber pneumatic spreading process was observed by according to the filament count, sizing content of carbon fiber and process variables in spreading equipment (fiber tension at the beginning, air temperature in spreading zone, vacuum pressure in spreading zone). Tensile strength was evaluated using samples prepared under optimal conditions for each of the carbon fiber varieties, and mechanical properties were reduced due to damage on the carbon fiber.